The stratosphere is cooler than the ground primarily due to the effects of CO2 as a greenhouse gas in the troposphere. Increased CO2 levels slow the escape of longwave radiation from the troposphere to the stratosphere, resulting in a warming troposphere and a cooling stratosphere. If CO2 levels stabilize, the troposphere would continue to heat until energy entering and leaving it balances, potentially normalizing stratospheric temperatures. Additionally, temperature decreases with altitude in the troposphere due to thermodynamic principles, while the stratosphere warms at higher altitudes due to UV absorption by the ozone layer. The discussion emphasizes the importance of avoiding global warming debates to focus on atmospheric processes.